Role based system for command and control

ABSTRACT

A system for enabling tracking and communication between units in a team, typically used for military or rescue operations. The system, known as Command and Control System, has a handheld central unit with a display for showing positions of team units and portable team units having GPS, compass and radio communication function for sending and receipt of positions and alarms and for receiving text messages, a display for showing own positions and bearings. The units have the ability to send data directly or relayed between each other and that each unit can be assigned one or more roles.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/995,375, having a filing date of Apr. 8, 2011, entitled ROLEBASED SYSTEM AND DEVICE FOR COMMAND AND CONTROL, which claims priorityto a 35 U.S.C §371 of International Application No. PCT/NO2009/000196,filed May 26, 2009, which application claims priority to NorwegianPatent Application Serial No. 20082556 filed May 30, 2008, the entiretyof all of which are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

The present invention relates to a system and a device for wirelesscommunication and more particularly to a communication system consistingof a central unit and portable team units with positioning capabilityand the ability to send and receive information between each other. Formilitary and rescue operations such systems, or groups of such systems,are often called Command and Control Systems (abbreviated to CCS orC2S).

BACKGROUND OF THE INVENTION

Current portable wireless communication terminals for military and fielduse have the ability to communicate with other similar devices over alarge area and have map systems that show an abundance of informationthat can be shared. They also have the ability to send audio messages tothe other terminals in form of peer to peer voice messages like thesimilar “walkie-talkie” technology.

However there are situations where large complex systems with maps andaudio communication are not favorable, in certain field situations thereare advantages to having a communication units that can be operatedsimply and that does not show unnecessary information; there are alsocertain situations where it is an advantage to communicate via textmessages and not through audio messages, like in areas with a high noiselevel e.g. during an emergency, or a catastrophe, or areas where thereis an advantage to keep a low noise level e.g. in a military operation.In these situations it is crucial that the unit is easy to operate andthat the information shared by the different units does not reach thewrong person(s). In these situations it is also favorable to have theability to communicate with all the other team units. In certainsituations like in a rescue operation or in a military operation it isalso an advantage to assign the different units one or more roles thatcan be displayed to the other units, reflecting the unit's tasks. Thisrole must be possible to change, both from the unit itself, or fromunits with a relevant role. E.g. a team leader can assign roles to itsteam members, but if the team leader (TL) is taken out of operationanother unit must be able to take the role as team leader.

It is known from the Norwegian Military publication FFI Fakta and frompatent application WO 2009145638 that a system designated “Normans KKI”and “Normans ledelse” includes a unit (KKI) to be placed and integratedby wire on a soldier's dress in order to make information aboutpositions of the soldier and designated team members show up on adisplay of the unit. The unit contains a digital magnetic compass and aGPS and also a simple message function enabling for example alarmmessages. Passive sensors can be coupled to the unit. The “ledelse” unitis a handheld unit that shows the positions of all soldier unitsdisplayed on a digital map giving the leader an overview of his team.The “ledelse” unit is supplied with software for interactive planningwith the units of the soldiers. Marching routes, way points or otherbattle related information can be put into the digital map. Also, activesensors can be coupled to the “ledelse” unit and information frompassive sensors on the soldiers' units can be collected. The messagefunctions of the “ledelse” units allow for sending and reception ofmaps, text, orders, alarms and positions.

The systems available at the present like the one in US 2006/0238331 A1shows a communication unit mainly for military use that has a GPS basedmap interface displaying the location of other team units. Thisinformation is shared between the different team units by radiocommunication via a central unit that receives the information,organizes it and sends it back out to the different team units in thesystem in a strict hierarchy, using a master-slave configuration. Thedifferent team units can also receive audio messages either from thecentral unit or from each other. These team units have in addition tobiosensors that monitors the pulse, temperature and blood pressure alsoabilities for iris scan of the user and a credit card chip for economicsettlement.

Similar systems are known from US20120077536 A1 that handle roledesignation, U.S. Pat. No. 8,705,714 that discloses a telecommunicationand multimedia management method that enables users to participate intactical communications, where media types could be e.g., location, orsensor information. These systems could be implemented with units usingoperative systems such as Android and in the form of smart phones withusing commercially available telecommunication such as GSM, 3G, 4G, LTEand WiFi mobile communication.

Further it is known from U.S. Pat. No. 6,898,526 B2 a communicationterminal system intended for hunters that has a GPS based map system anda radio communication device for communicating your position to acentral unit, the central unit sends the location of the different teamunits to each team unit. The information is shown on a map interfacewith a compass bearing, the team unit then further communicates with theweapon in the form that it always knows where it is pointing and canstop the weapon from firing in the direction of other team units. Thissystem does not have the ability to communicate any other informationthan the location information received from the GPS unit.

It is also known from U.S. Pat. No. 6,373,430 B1 a portable team unitwith GPS and radio that communicates the location information from theGPS with one or more other equal team units. The location information issent over the radio link to the other team units. This information isshown in a map interface so that everybody in the system can see wherethe others are by showing a unique identification tag for each teamunit.

U.S. Pat. No. 6,456,938 B1 teaches a system for navigation at a golfcourse, having a screen for showing a map of the course. The system hasmessages, and can show distances and bearings. The units may communicatedirectly, but cannot relay messages, nor show other player's position.US2005/0001720 A1 and US2008/096519 A1 both teach systems that tracksmobile terminals and where a unit can have a role as e.g. “leader”.

US2005/0001720 A1 and US2008/096519 A1 both teach systems that tracksmobile terminals and where a unit can have a role as e.g. “leader”.

US20140025848 A1 discloses how smart phones and tablets can beconnected, tethered, to military network communication equipment,enabling them to communicate in such networks.

Many solutions exist for providing secure communication for units usingcommercially available operative systems such as Android, where thesoftware can be provided in the form of downloadable applications, alsocalled “apps”, or are delivered included with or embedded in the unit.

Neither of these solutions or disclosures solve the problems of avoidinga third party to use a lost or compromised unit, or that a unit may bediscovered, disturb other communication or use too much battery becauseit transmits with unnecessary high power.

To the extent that specific patents/publications/products are discussedabove in this background Section or elsewhere in this application, thesediscussions should not be taken as an admission that the discusseddisclosures are prior art for patent law purposes. Some or all of thediscussed disclosures may not be sufficiently early in time, may notreflect subject matter developed early enough in time and/or may not besufficiently enabling so as to amount to prior art for patent lawpurposes. To the extent that specific disclosures are discussed aboveand/or throughout the application, the descriptions/disclosures of whichare all hereby incorporated by reference into this document in theirrespective entirety(ies).

SUMMARY OF THE INVENTION

The System

The system of the present invention consists of control and team units.In an embodiment there is one control unit, typically used by the teamleader, and several team units that all have roles. The units comprisesmart phones or pads running an operating system (OS) such as Android orWindows, among other operating systems know in the art. The positions ofall team members are indicated on the displays, and the units cancommunicate with data messages directly or relayed with one another.Communication to other teams or to a headquarters is in normalsituations done from the control unit only using another tacticalcommunication system that may be tethered connected. In an embodiment,all communication is encrypted, using asymmetric encryption todistribute a key for symmetric encryption to be used for a period.

The Team and Control Units

The unit of the present invention is a small communication unit forsoldiers, first responders such as fire fighters and the like. It hasintegrated radio transmission and receiving means, compass andpositioning utilities. The unit communicates with all other teammembers' units including a central unit usually with the team leader,giving the users a visual presentation of all team members' position.All units have been allocated particular roles within the team and theircurrent role is also displayed on other team members' units. The unitincludes means for sending and receiving various messages to and fromother team members, alarms and information from both active and passivesensors available within the current team.

The control unit of the present invention can be similar to a generalteam unit, the only difference being that the control unit has aparticular role set, such as “team leader”, and may have a particularsymbol 511, such as the pentagon shown in FIG. 5. In an embodiment thecontrol unit is responsible for configuring the encryption for the team,i.e. to initiate distribution of the symmetric key to be used. Thecontrol unit thus has stored, or the user enters, the public keys forall team members, whereas the team units, or their users, only need toknow the public key of the control unit. In a preferred embodiment, thecontrol unit also has a screen with resolution suitable for displayingmaps, and the positions of the team units can be shown overlaying themap. The control unit may also have a more powerful transceiver than ateam unit, communication devices for sending and receiving informationoutside of the team, an improved GPS receiver, a display with betterresolution, and a device for text input to compose message, rather thanselecting predefined messages from the menu.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of team unit;

FIG. 2 is a front view of a team unit with four buttons;

FIG. 3 is an example communication flow in a team, with team units,central unit and sensors;

FIG. 4 is an example message format;

FIG. 5 is an example team unit display with alarm and out of boundsarea;

FIG. 6 is an example team unit display with waypoint;

FIG. 7 is an example team unit display with alarm message;

FIG. 8 is an example team unit display with bearing only;

FIG. 9 is an example team unit display on low resolution screen;

FIG. 10 a-b: Menu structure of one embodiment;

FIG. 11: Alarm displays indicating acknowledgement needed;

FIG. 12 a-b: Menu structure of a second embodiment;

FIG. 13: An alternative embodiment of the team unit with six buttons;and

FIG. 14 a-i: Menu structure of a team unit with six buttons.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a block diagram of a unit. A bus is used for communicationbetween the various modules. In a preferred embodiment, severaldifferent buses are used for interconnecting the modules: SerialPeripheral Interface (SPI) is used between the microcontroller andmemory. Philips I2C used between the microcontroller and the compass,UART [universal asynchronous receiver/transmitter] is used between themicrocontroller and the other modules. There are positioning and compassmodules for positioning information. In a preferred embodiment thepositioning module cannot be set in stand-by power mode by commands onthe communication bus, but rather by controlling the power to themodule. When the positioning module is turned on, it will remember itsformer settings and start searching for satellites based on thisinformation. The transceiver is used for data communication with otherteam members. The remote device controller is, for example, usingBluetooth or other suitable protocols for communication with sensors.The display shows the information, for example, on a screen, but couldalso be a head up visor or retinal display or a touch screen. Themicrocontroller runs the state machine and memory is used both by themicrocontroller, but also for storing messages and for loggingpositioning and sensor information, so that the unit may function as ablack box where information can be recovered in case the unit's movementand sensor readings need to be recovered.

The memory may include non-volatile and/or volatile memory. For example,non-volatile memory may include a hard drive, flash memory, memory stickand the like. Also, volatile memory may include random access 10 memoryand others known in the art. In one embodiment, memory includesnon-transitory computer readable medium that stores program instructionsthat cause the respective unit to perform unit functions describedherein. The microcontroller could be a simple one without operativesystem, or an advanced one like Atmel's AT91SAM9G45 and AT91SAM9M10microcontrollers based on the ARM926 processor core, and with supportfor operative systems such as Android, Linux and the embedded version ofMicrosoft Windows. The local input device controller is handling the useof the buttons, but could also handle e.g. a touch screen or other inputdevices directly connected to the unit. Input devices such as a keyboardcan also be connected to the remote device controller, unique e.g.Bluetooth. To allow for optimized power saving abilities, each modulecan be controlled individually by reducing power consumption (forinstance by reducing power transmission) or being switched off.

The team units 200 could be implemented as smart phones, i-pads, on PCsand the like. The software could be in the form of a downloadableprogram application, often called “app”.

FIG. 2 is an illustration of one embodiment of a team unit 200.According to this embodiment, the team unit has a screen 210 forpresenting information to the user, two buttons 220 for scrollingthrough user menu and two buttons 230 for navigating inwards or outwardsin the menu structure. The unit is designed for use under stressfulcircumstances and in hard conditions, with a simple and logicalinterface.

In this embodiment, the team unit 200 has a built in position receiverused to receive positioning signals and calculate the user's ownposition. Various positioning means could be used in the presentinvention, e.g. GPS, GALILEO, GLONASS etc. In one embodiment, theposition receiver is a GPS receiver, for instance the LEA-5 from uBlox,that also supports GALILEO. In order to ensure optimal positioningsignal strength, the antenna is mounted on the highest point of theunit. In this embodiment, the unit can receive signals from up to 16satellites at one time, ensuring optimized accuracy of positioning data.Like all other electronics in the unit, the positioning module isdesigned to work with minimum power consumption. The positioning unit iscommunicating with the team unit control chip and radio transmissionmeans for sending its own position to all other team members. For anembodiment using a smart phone, such communication could use e.g. WiFior being tethered to a military radio.

In addition to the positioning module, the unit 200 also has a build incompass module. In one embodiment, the compass module is a digitalmagnetic compass module having 2 magnetometer sensors mountedperpendicular to each other. The two magnetic sensors register themagnetic field surrounding the two axes, representing the earth magneticfield if no other magnetic fields are present. While this particularcompass module requires the unit to be held in a horizontal positionwhen reading the information, other compass units may be used to betterensure reliable data at all times. The compass information is onlytreated when the unit is set to “compass information” mode.

The team unit can also be equipped with a short range radio device, likeBluetooth, for communicating with various sensors and the like. It couldalso be used to connect the team unit to other personal equipment, forinstance personal radio communication or sound devices.

In one embodiment, the core of the unit is a microcontroller,specifically designed to operate without the need of an operatingsystem. This ensures better and safer operating status, and a betterprotection against Electro Magnetic Pulse (EMP) attacks. Internal memoryis used for logic and communication control, while at the same timegiving the ability to store information, like, for instance, messages,waypoints and positioning log. In one embodiment a commerciallyavailable operative system such as Android, Windows, Linux or AppleiOSis used. Here the operative system will handle all in- and output andstorage including for messages, display, waypoints, and positioninglogs. In another embodiment the software is additionally in the form ofa downloadable application.

In one embodiment, the team unit includes a non-transitory computerreadable medium storing instructions for tracking and communicatingbetween units in a team, which when executed by a mobile device, causethe mobile device to display a position of the mobile device andpositions of other units, display all distances and bearings to otherunits relative to the mobile device, send data directly or relayedbetween other units, and send or receive at least one messageinstructing at least one of the following actions: deleting information,turn on, turn off and change power consumption. The mobile deviceincluding a plurality of buttons in which the plurality of buttonsincluding at least two or more buttons that require simultaneousactivation.

In one embodiment, the handheld central unit includes a non-transitorycomputer readable medium storing instructions for tracking andcommunicating between units in a team, which when executed by a handheldcentral unit, causes the handheld central unit to: provide a digitalmap, display positions of a plurality of portable team units on thedigital map, receive text messages, position information and alarms fromthe plurality of portable team units, send text messages, positioninformation and alarms to the plurality of portable team units, assigneach portable team unit at least one role, communicate at least onemessage containing an instruction selected from a group of: deletinginformation, turn on, turn off and change power consumption, and use ahop counter or time information to control propagation of messages.

In one embodiment, all data received from the positioning module as wellas sensors connected to the unit are stored in the memory module. Inorder to optimize for detailed logging information or high performance(low power and memory consumption), the logging update information couldbe adjusted accordingly (e.g. every 10 seconds or every 1 minute). Aftercompletion of an assignment, the users' movement and data from thesensors can be reviewed and evaluated. The complete session can bereplayed, and the team can evaluate their performance based on accuratehistorical information. For training sessions or preparations forimportant missions, this feature can improve the overall performance ofthe team, making them aware of their movements in relation to other teammembers as well as evaluate the importance of information given from thesensors. In specific cases, for instance if a fallen soldier has beenidentified at the battlefield, the logging information could helpexplain the course of events. Both information about his/her movement,and information from the sensors, could give valuable information.

In one embodiment, two memory chips are used, one for central storingand one for additional use if needed. The memory chips are responsiblefor storing messages received to the unit, predefined messages that canbe sent to the master unit, and received waypoints and other statusinformation. All memory chips and controllers are selected based ontheir low power consumption, reliability and number of connectionoptions. In one embodiment, the micro controller uses 3.3 V with a clockfrequency of 7.3728 MHz, ensuring good output and to better comply withthe frequencies used in serial communication.

In an embodiment of the invention, the team unit is operating using astate machine running a continuous loop, thus it does not need anytraditional operating system. The core of the software is a statemachine, always deciding what to be displayed and which next states arelegal. The compiled software from the implemented controllers andelectronic devices are loaded into a flash memory, and is automaticallyloaded when the unit is turned on. The state machine is running througha continuous loop, and certain modules are in operation at all times.Such continuously operating modules are, for instance, checking forbutton inputs, sending and receiving positioning information,registering communication between installed hardware etc. Both externalinformation, like pushing one of the four buttons, or internalinformation, for instance information from one of the implementedmodules, are deciding the next state.

As a state machine without an operative system, the unit is robust, andwill in case of an error condition restart and enter a valid state. Thisis achieved by having a counter that is reset in the main loop, called a“watch dog”, where reset is triggered if an error situation occurs.Error conditions can occur, for example, after the unit has been exposedto an Electro Magnetic Pulse (EMP).

For situations where it is necessary that information must be treatedimmediately, the system uses an interrupt message to stop the continuousloop. A bit flag is set to warn the system about an interrupt, and theinformation is treated accordingly. Such information could be input toturn off the button lock, GPS signal information or saving incoming datain the memory chip. When receiving positioning data, the data isvalidated using Cyclic Redundancy Check (CRC) to ensure that the dataflow is not corrupted. The data received from the positioning unit, likecurrent position, GPS clock and data, is then being analyzed and storedin the memory unit.

FIG. 3 shows a team with team units TU1 to TU4, a control unit CU, threesensors S1-S3 and two control units for other teams CUA and CUB. CUcommunicates with TU1 and TU2. Data, e.g. positioning information,alarms and sensor readings from TU3 and TU4 is relayed by TU2. As allunits in the team can both communicate directly and relay for otherunits, the position from TU3 is sent via TU2 to reach TU4. In oneembodiment, the control unit may be a personal computer. In oneembodiment, the team units may be mobile wireless devices such assmartphones, tables, personal digital assistant and the like, that runone or more operating systems such as Android, Windows, Linux and/orAppleiOS. In order to control, e.g., stop, propagation of messages inthe team when using the relay function, a hop count flag can be set inthe message header. For instance, the message is only allowed to berelayed three times, setting the maximum hop count to three. In thatcase, when a relay message is received the hop count flag is decrementedby one, and if larger than one the message is relayed. If the hop countequals zero after being decremented, the message will not be relayedfurther. In an alternative embodiment, time information is used ratherthan hop count. A sensor can be connected to one or more units, as isshown for S2. In this preferred configuration of the system, only CU isallowed to communicate outside the team, and is here shown tocommunicate with the control units of two other teams, CUA and CUB.

In special situations or for saving battery power, it can be importantto transmit with as low a power as possible. In an embodiment the powertransmitted varies between 10 and 500 mW, the latter giving a range ofup to 6 km. In one mode of communication messages are normally sent asencrypted broadcast messages. FIG. 4 shows message formats, includinghow only parts of the message need to be encrypted. If messages are notacknowledged, then the transmission power could normally be adjusted up.However, to transmit with low power, it is possible to enter acommunication mode, where other units are used as relay, as shown inFIG. 3. The communication mode could be set from the control unit, e.g.by sending a message indicating threat level, or by particular alarmmessages, such as a gas alarm. It is also possible to indicate the powerlevel in the messages. In FIG. 4 is a message format shown that useshalf a byte to indicate the power level that has been used for sendingthe message. Various schemes can then be used, e.g. starting to transmitwith low power and stepping it up until a level is reached where themessages are acknowledged.

In an embodiment, the protocol used for communication is based on lowpower 8-bits microcontrollers, and are specifically designed to beoptimized for low bit rates, high flexibility and allowing for largevariation in message size and radio transmission frequencies. Inaddition, the protocol is designed for carrier independentcommunication, meaning that the data can be sent independently fromunderlying network structure. The protocol has three main parts;

-   -   A generic data format encapsulating different types of messages    -   An acknowledge message, used in the systems reliability        mechanism    -   Different types of messages

In the message protocol, predefined message types are implemented, alsopresented in table 1.

TABLE 1 Size Acknowl- Message Content (byte) edgment Note Pos Longitude,9 No The unit's own Latitude position Text Text 0-245 Yes Free text orpredefined message BattStatus Battery 2 No Indicates battery statusstatus for attached Smart Battery AmmoStatus Ammunition 2 — statusCasualty Longitude, 9 Yes Indicates casualty Report Latitude or injuryat a given location Contact Longitude, 9 Yes Indicates hostile ReportLatitude detection from a given position Waypoint Longitude, 9 YesStored waypoint Latitude Poll Request for 2 No Used for requestinginformation information from team unit after a given message type (e.g.battery status or position) TeamPos Longitude, 10  No For relaying teamLatitude, units' positions Pos-age to units outside of current team

In one embodiment of the invention, the following message types areimplemented; “Pos”—for sending team unit position to all team members,“Text”—predefined messages from the team unit or composed messages fromthe central unit, “BattStatus”—information about power status of theunit, “AmmoStatus”—information about the user's ammunition status,“Casualty Report”—injury or damage in a certain position, “Contactreport”—enemy contact from given position, “Waypoint”—stored waypoint,“Poll”—request for information (e.g. battery status, position etc.) and“TeamPos”—from central unit to other central units or above ranked unitsregarding current team position. Most of the messages includepositioning information from the sender, and at the same time somemessages require the respondents to acknowledge the reception of themessages with an “Ack” message. Although various specific messages havebeen presented here, the protocol is not limited to these message typesonly. Additional types can be added if needed.

FIG. 4 is illustrating one possible implementation of a messagestructure. The structure can be used in an embodiment with a separatemessage structure, or partly or totally using message structures thatare available from the operative system with protocols such as IP (IPv4and IPv6) with protocols like TCP and UDP. The message could be anall-to-all message, for instance alarm message, a predefined messagestored in the team unit, or various status messages. When sending amessage from the team unit, the message header is first assembled fromthe following fields; sender address, size of the data field,destination address, acknowledge flag and sequence number. The header,together with predefined preamble and verification fields are used tocalculate the header check sum. After assembling of the header, datafields are added and the check sum calculated. The message is then sent,and if the message requires an acknowledgement the message is queueduntil acknowledge is received from the recipients and then deleted fromthe message system. If no acknowledgment is required, the message isdeleted immediately.

In one embodiment the messages are encrypted, using a common symmetricencryption method such as the Advanced Encryption Standard (AES). As themessages may be relayed by several units that need not read the contentof the message, the header is unencrypted. The AES key can bedistributed and changed using Public-key cryptography, where the privatekeys may be set in firmware for each unit, and the public keys ofpossible team units can be stored or exchanged when the units aredistributed to the team. The units may also communicate withoutencryption or they can have a default AES key to be used when an AES keyhave not been distributed using the Public-key cryptography. If aparticular unit is lost or compromised, a self destruct message could besent. Such a message could for instance inform the device to initiate anerasure of all vital information, and only transmit messages (forinstance position messages) unencrypted on an open channel. Thisprevents the lost unit from compromising the position and messageinformation sent between the other team members, while at the same timebeing able to keep track of the lost unit. In another embodiment, onlythe remaining units could update their symmetric encryption key (AESkey) and in that way avoid sending information to the compromised unit.

When receiving a message, the message header is first collected and thecheck sum is calculated and compared to the value in the header. If thecheck sum is not correct, the message is deleted. If the receiveridentification is not identical to the header destination or the messageis not a broadcast message, the message will be disregarded. If themessage is an acknowledge message, the sequence number is read and themessage is put in the out queue. If the message is a data message, itwill be stored in the internal unit memory. If the message is anacknowledgement message, the acknowledge message is produced based onsender address, sequence number and status, and then returned to thesender either automatically or when the user acknowledge that themessage has been read.

FIG. 4 shows different message formats. The topmost message format is asimple, unencrypted format. The middle message is the data part of amessage for positioning used when a unit reports its position. Inaddition this part has fields for vital sensor information, such asheart rate. The message at the bottom of the figure is a message forencrypted communication, where, for example, positioning data as shownabove, can be placed. The format allows several teams to operate on thesame radio channels, as the messages have address fields indicationdestination team and unit (DestinationL). The SessionID field indicateswhich AES key is used for the following encrypted part, and thus a unit,normally a control unit, may belong to more than one team.

In FIG. 3, an embodiment of the presented invention, the systemcomprises one central unit and one or more team units, with all-to-allor one-to-all communication. In addition, sensors can be connected tothe units e.g. using short range radio transmission (i.e. Bluetoothtechnology), sharing specific environmental information or informationabout the user of the team unit (i.e. heart beat or body temperature).The sensors can be active, such as a laser measuring distance or atriggered camera, or passive such as a heart rate sensor or a gasdetector. Sensors could be classified as passive or active. The passivesensors are sensors not relying on actions from a user in order to beactive. They are monitoring specific features continuously, for instancebio sensors or gas detection units. Active sensors are sensors operatedactively by a user, for instance a laser distance measurement device.All sensors could be operated by any user in the team, and thecommunication module in the unit makes it possible to transferinformation from one sensor to all members of the team.

The central unit also has the ability to send messages to other centralunits in different teams or to a higher ranked unit (for instance atroop command post). The messages could be positioning information, textmessages, alarms, pictures and other useful information, using a messagestructure and protocol similar to the one used in the present invention,or using another tactical communication system.

In one embodiment in order to show the information to the user, the unitis equipped with a small screen interface, for presenting information tothe user having both text and simple graphics. The screen is designedwith two back light sources for ease of use and security reasons, onewith traditional light and one with infrared (IR) back light, the latterfor use in combination with night vision equipment. In daylight, thedisplay is reflecting available light, making it optimal for reading insunlight. In order not to reveal the user's position, for instance toenemy forces, the display can be inverted in order to reduce the amountof light to be radiated. The display brightness is adjusted using pulsemodule signals, turning the diode lights on and off with a highfrequency e.g. a duty cycle of 1/250. Other methods for avoidingdetection could be used, e.g. different pulsing of light source,fluorescent backlight or night vision.

FIGS. 5 and 6 shows the display of a team unit. The unit itself isdisplayed in the middle as a circle with role information 510; the roleis here shown as G1, e.g. meaning first gunner. Another team unit isshown as G2, e.g. meaning second gunner. This team unit is displayed inred, indicating a gas alarm, from a sensor connected to this unit. Ascan be seen in FIGS. 7 and 10, alarms can also be indicated as messageson the screen. FIG. 7 shows an alarm displayed as an overlay message.This alarm does not indicate the need for acknowledgement, as the alarmsin FIG. 10. All positioning information is shown in relation to its ownposition and orientation. The circle 520 is a presentation of thecurrent range resolution, the current radius of the circle is presentedat the lower right corner of the screen; 530. Other team members' andsensors' positions are presented as small circles with information aboutthe current role of the unit. There are many other ways of presentingbearing and distance information on the display, e.g. by use of vectors,waypoints, distance information for all team member and symbols. Thescale of the display could also be dynamically changed, e.g. based onthe distance to the furthest unit, and this new scale could be indicatedby the distance.

FIG. 8 shows only the bearing to other units, and not the distance. Thisis useful, for example, if the team members all are very close, or somemembers are far away. In this embodiment the lack of distanceinformation is indicated by the radius of the distance indicating circleshown as 0 m and the circle is dashed. There are other ways ofindicating that only bearing is displayed.

The possible roles can be predefined in a list in the menu, or theycould be freely set, e.g. by entering text for predefined roles ordefining new roles as the text is entered. A role serves severalpurposes: it may inform the other team members of duties and expectedbehavior, it may give certain rights to configure the system or sendalarms, or it may indicate the use of specialized sensors. Examples ofroles are: Machine Gunner, Gunner, Senior Fire Fighter, AuxiliaryFirefighter, Medic and Rescue Worker. Roles can be changed and a unitmay have more than one role. The roles could be changed on the unit inquestion or from the central unit, and there could be set of rulesdefining which changes are allowed.

The Central Unit is here shown as a black pentagon 511. Additionalgeographical information concerning the surrounding area could also besent to the team unit and presented in the display. Such informationcould for instance be “Out of bounds” areas 540; areas where the teammembers are specifically forbidden to enter (like mine fields etc.).When an alarm message is sent from one of the team units, all other teamunits are warned and the position of the unit sending the alarm ishighlighted in the display (G2). The display will always be oriented inthe same direction as the team unit, and based on range and angle to theother team members, the user will always be able to determine thecorrect position of all team members. A line indicating the direction toNorth or a predefined direction on the Earth is also displayed (550),ensuring that the team member is appropriately oriented to thesurrounding area.

A unit that has lost positioning information, e.g. from being inside abuilding, can be indicated on the team's displays with information onhow long the unit has been without positioning information or howuncertain the position is. The assumed position can be estimated by deadreckoning, and the uncertainty can be graphically indicated, e.g. byblurring the unit on the display.

FIG. 9 shows a display for a low resolution, monochrome display. Batterylevel and GPS reception level is indicated. An envelope indicates newmessages. A key indicates encrypted mode. Time is shown as 15:31. Thedistance to a waypoint is shown as 65 m and the R=50 m indicates thescale by giving the radius of the circle. The display is inverted, asnot to radiate more light than needed. Other team members are indicatedwith O, 1 and D.

In one embodiment, the menu structure in the team unit is designed to beoperated with four buttons. Two buttons are used for scrolling in themenu system, while the two others are used for selecting or deselectingthe different alternatives. FIG. 10 shows additional menu structures,and how the user is able to navigation by using the four buttonsavailable in the team unit. The menu system is designed to allow forquick access to specifically important messages, for instance enemycontact. These messages are referred to as set click messages. In oneembodiment, the right button could be used for selecting predefinedmessages directly. One click gives the user an overview of the messagemenu, the next click selects predefined messages, the third clickselects alarm messages and the fourth click sends an enemy contactalarm. In this way, the user is given the ability to select the messageenemy contact without having to look at the unit, while at the same timeminimize the chance of sending an alarm message unintentionally. In caseof enemy contact, the user can select the alarm message by clickingrapidly four times on the right button, without having to take his/herseyes of the enemy. Different menu structures and button combinationscould be used to allow for more than the one set click message describedhere.

FIGS. 10 a and 10 b show a possible implementation of the menu structurein the team unit, designed to be operated with four buttons. Two buttonsare used for scrolling in the menu system, while the two others are usedfor selecting or deselecting the different alternatives. In the case ofan implementation on a unit with touch screen, these buttons will beareas to press on the screen, or commands using one or more fingers,pressing and sliding on the screen. FIGS. 11 and 12 show additional menustructures, and how the user is able to navigation by using four buttonsavailable in the team unit. The menu system is designed to allow forquick access to specifically important messages, for instance enemycontact. These messages are referred to as set click messages. In oneembodiment, the right button could be used for selecting predefinedmessages directly. One click gives the user an overview of the messagemenu, the next click selects predefined messages, the third clickselects alarm messages and the fourth click sends an enemy contactalarm. In this way, the user is given the ability to select the messageenemy contact without having to look at the unit, while at the same timeminimize the chance of sending an alarm message unintentionally. In caseof enemy contact, the user can select the alarm message by clickingrapidly four times on the right button, without having to take his/herseyes of the enemy. Different menu structures and button combinationscould be used to allow for more than the one set click message describedhere.

FIG. 11 shows alarms that overlays the display. The right handindication of “understood” is also an indication of which button, orwhere to press, to be used for a one-click acknowledgement of receipt.

FIG. 12 shows an alternative menu structure for a four-button team unitas of FIG. 2. The scroll buttons 220 are used for scrolling in thechoices as indicated and the right select button 230 is used forselecting.

FIG. 13 shows an embodiment of a team unit with six buttons. The twoside buttons operates as a single input command; both buttons need to bepressed to activate. This gives in effect a five button unit, but withadded confidence when using the fifth button, in that the two halves ofthe button are placed on adjacent sides of the unit. In the case of atouch screen implementation, this could be two separate areas, or onearea and one button on the unit. This button can e.g. be used for givingcritical alarms such as enemy contact or reporting injuries. FIG. 14 a-ishows the message structure for this embodiment in which FIG. 14 aillustrates the overall message structure. FIGS. 14 b-i each illustratedifferent portions of the overall message structure.

What is claimed is:
 1. A system for tracking and communicating betweenunits in a team comprising: a plurality of portable team units, eachteam unit having: a GPS module; a compass module; a display showing theposition of the unit and positions of other team units; a radiocommunication module, the module having a transmitter and receiver; amemory component for storing position information, alarms, and textmessages; a handheld central unit having: a digital map; a displayshowing positions of team units on a map; and a transmitter and receiversending and receiving text messages, position information and alarms;the handheld central unit communicating with other team units, assigningeach team unit at least one role, and communicating at least one messagecontaining an instruction selected from the group of: deletinginformation, turn on, turn off, and change power consumption; and thesystem configured to use a hop counter or time information to controlpropagation of messages.
 2. The system as set forth in claim 1 havingsaid communication in the system being selected from a group of: open,encrypted and partially encrypted.
 3. The system as set forth in claim 2having said partially encrypted communication being the payload of anencrypted message.
 4. The system as set forth in claim 1 having saidtext messages being predefined or typed and selected from a menu or setclick messages.
 5. The system as set forth in claim 1 having said unitssending messages that require acknowledgement of receipt.
 6. The systemas set forth in claim 1, wherein said units have a mode displayinginformation in a dark environment.
 7. The system as set forth in claim 6having said mode using infrared backlight, pulsing of a light source,fluorescent backlight or night vision.
 8. The system as set forth inclaim 1 having said text message including a power level valueindicating the level of power of the message.
 9. The system as set forthin claim 1, wherein said units use active sensors.
 10. The system as setforth in claim 1, wherein said compass module has an arrow pointing at apredefined direction.
 11. The system as set forth in claim 1 having saiddisplay on the team unit showing an overlay of geographic information.12. The system as set forth in claim 11 having said overlay ofgeographic information being a marked out of bounds area or routeinformation.
 13. The system as set forth in claim 1 having said rolebeing chosen from a list.
 14. The system as set forth in claim 1 havingsaid role being set by entering text information of a predefined role.15. The system as set forth in claim 14 having said role being changed.16. The system as set forth in claim 1 having said display on the unitsindicating that at least one unit has lost positioning information. 17.The system as set forth in claim 1 having all distances and bearings toother units displayed relative to said handheld central unit.
 18. Thesystem as set forth in claim 1 having said units displaying onlybearings for some or all units.
 19. The system as set forth in claim 1having said units store positioning log and sensor information.
 20. Anon-transitory computer readable medium storing instructions fortracking and communicating with units in a team, which when executed bya device, cause the device to: display a position of the device andpositions of other units, display all distances and bearings to otherunits relative to the device, the device including a plurality ofbuttons, the plurality of buttons including at least two or more buttonsthat require simultaneous activation; send data directly or relayedbetween other units; and send or receive at least one messageinstructing at least one of the following actions: deleting information,turn on, turn off and change power consumption.
 21. The non-transitorycomputer readable medium as set forth in claim 20, having further storedinstructions, which when executed by the device, cause the device todisplay an overlay of geographic information.
 22. The non-transitorycomputer readable medium as set forth in claim 20, having further storedinstructions, which when executed by the device, cause the device todisplay information in a dark environment, using infrared backlight,pulsing of a light source, fluorescent backlight or night vision. 23.The non-transitory computer readable medium as set forth in claim 20,wherein the at least one message includes are one click acknowledgementmessages.
 24. The non-transitory computer readable medium as set forthin claim 20, having further stored instructions, which when executed bythe device, cause the device to display the roles of the other units.25. A non-transitory computer readable medium storing instructions fortracking and communicating with units in a team, which when executed bya handheld central unit, causes the handheld central unit to: provide adigital map; display positions of a plurality of portable team units onthe digital map; receive text messages, position information and alarmsfrom the plurality of portable team units; send text messages, positioninformation and alarms to the plurality of portable team units; assigneach portable team unit at least one role; communicate at least onemessage containing an instruction selected from a group of: deletinginformation, turn on, turn off and change power consumption; and use ahop counter or time information to control propagation of messages.